Fe.sub.3 Al intermetallic iron aluminides having a body centered cubic ordered crystal structure are disclosed in U.S. Pat. Nos. 5,320,802; 5,158,744; 5,024,109; and 4,961,903. An iron aluminide alloy having a disordered body centered crystal structure is disclosed in U.S. Pat. No. 5,238,645 wherein the alloy includes, in weight % 8-9.5 Al, .ltoreq.7 Cr, .ltoreq.4 Mo, .ltoreq.0.05 C, .ltoreq.0.5 Zr and .ltoreq.0.1 Y, preferably 4.5-5.5 Cr, 1.8-2.2 Mo, 0.02-0.032 C and 0.15-0.25 Zr.
Iron-base alloys containing 3-18 wt % Al, 0.05-0.5 wt % Zr, 0.01-0.1 wt % B and optional Cr, Ti and Mo are disclosed in U.S. Pat. No. 3,026,197 and Canadian Patent No. 648,140. U.S. Pat. No. 3,676,109 discloses an iron-base alloy containing 3-10 wt % Al, 4-8 wt % Cr, about 0.5 wt % Cu, less than 0.05 wt % C, 0.5-2 wt % Ti and optional Mn and B.
Iron-base aluminum containing alloys for use as electrical resistance heating elements are disclosed in U.S. Pat. Nos. 1,550,508; 1,990,650; and 2,768,915 and in Canadian Patent No. 648,141. The alloys disclosed in the '508 patent include 20 wt % Al, 10 wt % Mn; 12-15 wt % Al, 6-8 wt % Mn; or 12-16 wt % Al, 2-10 wt % Cr. All of the specific examples disclosed in the '508 patent include at least 6 wt % Cr and at least 10 wt % Al. The alloys disclosed in the '650 patent include 16-20 wt % Al, 5-10 wt % Cr, .ltoreq.0.05 wt % C, .ltoreq.0.25 wt % Si, 0.1-0.5 wt % Ti, .ltoreq.1.5 wt % Mo and 0.4-1.5 wt % Mn and the only specific example includes 17.5 wt % Al, 8.5 wt % Cr, 0.44 wt % Mn, 0.36 wt % Ti, 0.02 wt % C and 0.13 wt % Si. The alloys disclosed in the '915 patent include 10-18 wt % Al, 1-5 wt % Mo, Ti, Ta, V, Cb, Cr, Ni, B and W and the only specific example includes 16 wt % Al and 3 wt % Mo. The alloys disclosed in the Canadian patent include 6-11 wt % Al, 3-10 wt % Cr, .ltoreq.4 wt % Mn, .ltoreq.1 wt % Si, .ltoreq.0.4 wt % Ti, .ltoreq.0.5 wt % C, 0.2-0.5 wt % Zr and 0.05-0.1 wt % B and the only specific examples include at least 5 wt % Cr.
Resistance heaters of various materials are disclosed in U.S. Pat. No. 5,249,586 and in U.S. patent application Ser. Nos. 07/943,504, 08/118,665, 08/105,346 and 08/224,848.
U.S. Pat. No. 4,334,923 discloses a cold-rollable oxidation resistant iron-base alloy useful for catalytic converters containing .ltoreq.0.05% C, 0.1-2% Si, 2-8% Al, 0.02-1% Y, &lt;0.009% P, &lt;0.006% S and &lt;0.009% O.
U.S. Pat. No. 4,684,505 discloses a heat resistant iron-base alloy containing 10-22% Al, 2-12% Ti, 2-12% Mo, 0.1-1.2% Hf, .ltoreq.1.5% Si, .ltoreq.0.3% C, .ltoreq.0.2% B, .ltoreq.1.0% Ta, .ltoreq.0.5% W, .ltoreq.0.5% V, .ltoreq.0.5% Mn, .ltoreq.0.3% Co, .ltoreq.0.3% Nb, and .ltoreq.0.2% La.
Japanese Laid-open Patent Application No. 53-119721 discloses a wear resistant, high magnetic permeability alloy having good workability and containing 1.5-17% Al, 0.2-15% Cr and 0.01-8% total of optional additions of &lt;4% Si, &lt;8% Mo, &lt;8% W, &lt;8% Ti, &lt;8% Ge, &lt;8% Cu, &lt;8% V, &lt;8% Mn, &lt;8% Nb, &lt;8% Ta, &lt;8% Ni, &lt;8% Co, &lt;3% Sn, &lt;3% Sb, &lt;3% Be, &lt;3% Hf, &lt;3% Zr, &lt;0.5% Pb, and &lt;3% rare earth metal.
A 1990 publication in Advances in Powder Metallurgy, Vol. 2, by J. R. Knibloe et al., entitled "Microstructure And Mechanical Properties of P/M Fe.sub.3 Al Alloys", pp. 219-231, discloses a powder metallurgical process for preparing Fe.sub.3 Al containing 2 and 5% Cr by using an inert gas atomizer. To make sheet, the powders were canned in mild steel, evacuated and hot extruded at 1000.degree. C. to an area reduction ratio of 9:1. After removing from the steel can, the alloy extrusion was hot forged at 1000.degree. C. to 0.340 inch thick, rolled at 800.degree. C. to sheet approximately 0.10 inch thick and finish rolled at 650.degree. C. to 0.030 inch.
A 1991 publication in Mat. Res. Soc. Symp. Proc., Vol. 213, by V. K. Sikka entitled "Powder Processing of Fe.sub.3 Al-Based Iron-Aluminide Alloys," pp. 901-906, discloses a process of preparing 2 and 5% Cr containing Fe.sub.3 Al-based iron-aluminide powders fabricated into sheet. To make sheet, the powders were canned in mild steel and hot extruded at 1000.degree. C. to an area reduction ratio of 9:1. The steel can was removed and the bars were forged 50% at 1000.degree. C., rolled 50% at 850.degree. C. and finish rolled 50% at650.degree. C. to 0.76 mm sheet.
A paper by V. K. Sikka et al., entitled "Powder Production, Processing, and Properties of Fe.sub.3 Al", pp. 1-11, presented at the 1990 Powder Metallurgy Conference Exhibition in Pittsburgh, Pa., discloses a process of preparing Fe.sub.3 Al powder by melting constituent metals under a protective atmosphere, passing the metal through a metering nozzle and disintegrating the melt by impingement of the melt stream with nitrogen atomizing gas. An extruded bar was produced by filling a 76 mm mild steel can with the powder, evacuating the can, heating 11/2 hour at 1000.degree. C. and extruding the can through a 25 mm die for a 9:1 reduction. A sheet 0.76 mm thick was produced by removing the can, forging 50% at 1000.degree. C., rolling 50% at 850.degree. C. and finish rolling 50% at 650.degree. C.
Oxide dispersion strengthened iron-base alloy powders are disclosed in U.S. Pat. Nos. 4,391,634 and 5,032,190. The '634 patent discloses Ti-free alloys containing 10-40% Cr, 1-10% Al and .ltoreq.10% oxide dispersoid. The '190 patent discloses a method of forming sheet from alloy MA 956 having 75% Fe, 20% Cr, 4.5% Al, 0.5% Ti and 0.5% Y.sub.2 O.sub.3.
A publication by A. LeFort et al., entitled "Mechanical Behavior of FeAl.sub.40 Intermetallic Alloys" presented at the Proceedings of International Symposium on Intermetallic Compounds--Structure and Mechanical Properties (JIMIS-6), pp. 579-583, held in Sendai, Japan on Jun. 17-20, 1991, discloses various properties of FeAl alloys (25 wt % Al) with additions of boron, zirconium, chromium and cerium. The alloys were prepared by vacuum casting and extruding at 1100.degree. C. or formed by compression at 1000.degree. C. and 1100.degree. C.
A publication by D. Pocci et al., entitled "Production and Properties of CSM FeAl Intermetallic Alloys" presented at the Minerals, Metals and Materials Society Conference (1994 TMS Conference) on "Processing, Properties and Applications of Iron Aluminides", pp. 19-30, held in San Francisco, Calif. on Feb. 27-Mar. 3, 1994, discloses various properties of Fe.sub.40 Al intermetallic compounds processed by different techniques such as casting and extrusion, gas atomization of powder and extrusion and mechanical alloying of powder and extrusion and that mechanical alloying has been employed to reinforce the material with a fine oxide dispersion. The article states that FeAl alloys were prepared having a B2 ordered crystal structure, an Al content ranging from 23 to 25 wt % (about 40 at %) and alloying additions of Zr, Cr, Ce, C, B and Y.sub.2 O.sub.3.
A publication by J. H. Schneibel entitled "Selected Properties of Iron Aluminides", pp. 329-341, presented at the 1994 TMS Conference discloses properties of iron aluminides. This article reports properties such as melting temperatures, electrical resistivity, thermal conductivity, thermal expansion and mechanical properties of various FeAl compositions.
A publication by J. Baker entitled "Flow and Fracture of FeAl", pp. 101-115, presented at the 1994 TMS Conference discloses an overview of the flow and fracture of the B2 compound FeAl. This article states that prior heat treatments strongly affect the mechanical properties of FeAl and that higher cooling rates after elevated temperature annealing provide higher room temperature yield strength and hardness but lower ductility due to excess vacancies.
A publication by D. J. Alexander entitled "Impact Behavior of FeAl Alloy FA-350", pp. 193-202, presented at the 1994 TMS Conference discloses impact and tensile properties of iron aluminide alloy FA-350. The FA-350 alloy includes, in atomic %, 35.8% Al, 0.2% Mo, 0.05% Zr and 0.13% C.
A publication by C. H. Kong entitled "The Effect of Ternary Additions on the Vacancy Hardening and Defect Structure of FeAl", pp. 231-239, presented at the 1994 TMS Conference discloses the effect of ternary alloying additions on FeAl alloys. This article discusses the effects of various ternary alloying additions such as Cu, Ni, Co, Mn, Cr, V and Ti as well as high temperature annealing and subsequent low temperature vacancy-relieving heat treatment.
A publication by D. J. Gaydosh et al., entitled "Microstructure and Tensile Properties of Fe-40 At.Pct. Al Alloys with C, Zr, Hf and B Additions" in the September 1989 Met. Trans A, Vol. 20A, pp. 1701-1714, discloses hot extrusion of gas-atomized powder wherein the powder either includes C, Zr and Hf as prealloyed additions or B is added to a previously prepared iron-aluminum powder.
A publication by C. G. McKamey et al., entitled "A review of recent developments in Fe.sub.3 Al-based Alloys" in the August 1991 J. of Mater. Res., Vol. 6, No. 8, pp. 1779-1805, discloses techniques for obtaining iron-aluminide powders by inert gas atomization and preparing ternary alloy powders based on Fe.sub.3 Al by mixing alloy powders to produce the desired alloy composition and consolidating by hot extrusion, i.e., preparation of Fe.sub.3 Al-based powders by nitrogen- or argon-gas atomization and consolidation to full density by extruding at 1000.degree. C. to an area reduction of .ltoreq.9:1.
U.S. Pat. Nos. 4,917,858; 5,269,830; and 5,455,001 disclose powder metallurgical techniques for preparation of intermetallic compositions by (1) rolling blended powder into green foil, sintering and pressing the foil to full density, (2) reactive sintering of Fe and Al powders to form iron aluminide or by preparing Ni--B--Al and Ni--B--Ni composite powders by electroless plating, canning the powder in a tube, heat treating the canned powder, cold rolling the tube-canned powder and heat treating the cold rolled powder to obtain an intermetallic compound. U.S. Pat. No. 5,484,568 discloses a powder metallurgical technique for preparing heating elements by micropyretic synthesis wherein a combustion wave converts reactants to a desired product. U.S. Pat. No. 5,489,411 discloses a powder metallurgical technique for preparing titanium aluminide foil by plasma spraying a coilable strip, heat treating the strip to relieve residual stresses, placing the rough sides of two such strips together and squeezing the strips together between pressure bonding rolls, followed by solution annealing, cold rolling and intermediate anneals.
U.S. Pat. No. 3,144,330 discloses a powder metallurgical technique for making electrical resistance iron-aluminum alloys by hot rolling and cold rolling elemental powder, prealloyed powders or mixtures thereof into strip. U.S. Pat. No. 2,889,224 discloses a technique for preparing sheet from carbonyl nickel powder or carbonyl iron powder by cold rolling and annealing the powder.
Titanium alloys are the subject of numerous patents and publications including U.S. Pat. Nos. 4,842,819; 4,917,858; 5,232,661; 5,348,702; 5,350,466; 5,370,839; 5,429,796; 5,503,794; 5,634,992; and 5,746,846, Japanese Patent Publication Nos. 63-171862; 1-259139; and 1-42539; European Patent Publication No. 365174 and articles by V. R. Ryabov et al entitled "Properties of the Intermetallic Compounds of the System Iron-Aluminum" published in Metal Metalloved, 27, No.4, 668-673, 1969; S. M. Barinov et al entitled "Deformation and Failure in Titanium Aluminide" published in Izvestiya Akademii Nauk SSSR Metally, No. 3, 164-168, 1984; W. Wunderlich et al entitled "Enhanced Plasticity by Deformation Twinning of Ti--Al-Base Alloys with Cr and Si" published in Z. Metallkunde, 802-808, November 1990; T. Tsujimoto entitled "Research, Development, and Prospects of TiAl Intermetallic Compound Alloys" published in Titanium and Zirconium, Vol. 33, No. 3, 19 pages, July 1985; N. Maeda entitled "High Temperature Plasticity of Intermetallic Compound TiAl" presented at Material of 53.sup.rd Meeting of Superplasticity, 13 pages, Jan. 30, 1990; N. Maeda et al entitled "Improvement in Ductility of Intermetallic Compound through Grain Super-refinement" presented at Autumn Symposium of the Japan Institute of Metals, 14 pages, 1989; S. Noda et al entiitled "Mechanical Properties of TiAl Intermetallic Compound" presented at Autumn Symposium of the Japan Institute of Metals, 3 pages, 1988; H. A. Lipsitt entitled "Titanium Aluminides--An Overview" published in Mat. Res. Soc. Symp. Proc. Vol. 39, 351-364, 1985; P. L. Martin et al entitled "The Effects of Alloying on the Microstructure and Properties of Ti.sub.3 Al and TiAl" published by ASM in Titanium 80, Vol. 2, 1245-1254, 1980; S. H. Whang et al entitled "Effect of Rapid Solidification in L1.sub.0 TiAl Compound Alloys" ASM Symposium Proceedings on Enhanced Properties in Structural Metals Via Rapid Solidification, Materials Week, 7 pages, 1986; and D. Vujic et al entitled "Effect of Rapid Solidification and Alloying Addition on Lattice Distortion and Atomic Ordering in L1.sub.0 TiAl Alloys and Their Ternary Alloys" published in Metallurgical Transactions A, Vol. 19A, 2445-2455, October 1988.
Methods by which TiAl aluminides can be processed to achieve desirable properties are disclosed in numerous patents and publications such as those mentioned above. In addition, U.S. Pat. No. 5,489,411 discloses a powder metallurgical technique for preparing titanium aluminide foil by plasma spraying a coilable strip, heat treating the strip to relieve residual stresses, placing the rough sides of two such strips together and squeezing the strips together between pressure bonding rolls, followed by solution annealing, cold rolling and intermediate anneals. U.S. Pat. No. 4,917,858 discloses a powder metallurgical technique for making titanium aluminide foil using elemental titanium, aluminum and other alloying elements. U.S. Pat. No. 5,634,992 discloses a method of processing a gamma titanium aluminide by consolidating a casting and heat treating the consolidated casting above the eutectoid to form gamma grains plus lamellar colonies of alpha and gamma phase, heat treating below the eutectoid to grow gamma grains within the colony structure and heat treating below the alpha transus to reform any remaining colony structure a structure having .alpha..sub.2 laths within gamma grains.
Based on the foregoing, there is a need in the art for an economical technique for preparing sheet or strip of hard-to-work metal compositions such as iron, nickel and titanium aluminides. It would be desirable if aluminide compositions could be prepared by an economical technique in order to form an aluminide sheet product.